What does the verse say about "Yoshevei Ketzavos"?
Radak #1: [Even] people at the end of the land; everyone sees the Osos - "b'Chol ha'Aretz Yatza Kavam uvi'Ketze Sevel Mileihem; ...u'Sekufaso Al Ketzosam v'Ein Nistar me'Chamaso" (Tehilim 19:5, 7).
Radak #2: Just like [even] people at the end of the land feared the Osos that You did for Yisrael, e.g. Keri'as Yam Suf - "Sham'u Amim Yirazun" (Shemos 15:14), so they will fear You again when You gather the exiles.
Malbim: People who live at the east and west ends of the land, they saw Your signs and sang to Your name.
What results from Hashem's Osos?
Radak: From the wonders that he shows every day, people should fear Him, for there is a Conductor who leads them every day and night.
Malbim: People saw them and sang to Your name, and feared You. This refers to (a) the Osos of rain and clouds, and (b) the Os of Tzedek and Mishpat that Hashem showed in the episode of the Giv'onim, which made everyone fear and take Musar.
What is the meaning of "Motza'ei Voker va'Erev Tarnin"?
Rashi: The Osos that come out in the morning and at night (Radak - the moon and stars at night, and the sun in the morning) cause people who dwell in the ends of the land to sing to You. In the morning they say Baruch Yotzer ha'Me'oros, and at night Baruch Ma'ariv Aravim.
Radak #1: The Osos delight people after the morning and night, when they go out - "b'Ran Yachad Kochevei Voker va'Yari'u Kol Bnei Elohim" (Iyov 38:7). You make them delight, for You bring out the Osos!
Radak #2: The Osos that You did to make Yisrael delight when the morning and night came - You brought out the cloud during the day and the pillar of fire at night - so You will do for them when You gather the exiles!
Malbim: People who live at the east and west ends of the land.
